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Re: [boost] FW: Proposal for a Differential Evolution C++ library
by Adrian Michel 09 Jan '12

09 Jan '12

On 12/23/2011 10:07 AM, Dave Abrahams wrote: >> On 12.12.2011 06:52, Adrian Michel wrote: >> >> The full documentation is at http://www.amichel.com/de/doc/html but >> I'd >> suggest these pages for a first read >> http://www.amichel.com/de/doc/html/dd/d53/overview.html and >> http://www.amichel.com/de/doc/html/db/d4e/tutorial.html . > > This looks like important and useful stuff to me. > I was wondering what the status of this proposal is. So far several members have expressed interest, but there have been no new posts on this in a while, and I'm not sure what to expect next as far as the boost inclusion acceptance (or rejection) process. Adrian Michel www.tradery.com

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[iterator] Combining traversal_tags with iterator_tags
by Ronald Garcia 09 Jan '12

09 Jan '12

Hi, In MultiArray I would like use iterator_facade to create an iterator that can satisfy random_access_traversal, input_iterator_tag, and output_iterator_tag. I see that in the file boost/iterator/detail/facade_iterator_category.hpp, at line 138 there is a class in the boost::detail namespace declared template <class Category, class Traversal> struct iterator_category_with_traversal So it looks like passing: boost::detail::iterator_category_with_traversal<boost::detail::input_output_iterator_tag,boost::random_traversal_tag> as the CategoryOrTraversal would be what I want. However, two components above are in the detail namespace, so I am not sure if they are meant to be used by other libraries. Is this a safe operation? Thanks, Ron Side Notes: In my searches, I found a few buggy bits in the docs and code comments: - In boost/iterator/detail/facade_iterator_category.hpp, line 76, there's a comment: // If writability has been disabled per the above metafunction, the // result will not be convertible to output_iterator_tag. This comment corresponds to behavior that was removed in changeset: https://svn.boost.org/trac/boost/changeset/21683 Now the result will never be convertible to output_iterator_tag. - In the documentation for iterator_facade, there's a bit of a booboo where the function is first written: iterator-category(CategoryOrTraversal, value_type, reference) Then defined as: iterator-category(C,R,V) So I think the argument order is flipped.

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Is the review schedule up to date?
by Klaim - Joël Lamotte 08 Jan '12

08 Jan '12

Hi and happy new year, I just wanted to know if the review schedule page is currently up to date ( http://www.boost.org/community/review_schedule.html) I'm asking because I'm a bit surprised that so much proposed libraries don't have a review manager, so maybe it's just that they have not been noted on this page? Thanks. Joël Lamotte

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Re: [boost] [Boost.Move] [Boost.Container] Compiling with older versions of Boost and Performance
by Thomas Jordan 08 Jan '12

08 Jan '12

> Message: 3 > Date: Sat, 07 Jan 2012 15:58:20 +0100 > From: "Vicente J. Botet Escriba" <vicente.botet(a)wanadoo.fr> <snip> > Le 07/01/12 12:10, Thomas Jordan a ?crit : >> Hi, >> I am interested in experimenting with v1.48 Boost.Move and >> Boost.Container. However, I am otherwise constrained to using Boost >> libraries v1.33.1 with >> a Sun C++ v5.10 compiler. I couldn't seem any 'Boost library >> dependencies' listed in the Move/Container documentation, but a quick >> look through the header files suggests >> that it is mainly MPL and Type Traits. So... >> First question: would it be feasible for me to combine the headers for >> these two libraries with the v1.33.1 libraries and get it to work (albeit >> maybe with a little customisation), or would it be a big job/non-starter? >> Second question - I don't see any performance analysis published for >> Boost.Move. I know that move semantics is about more than improved >> performance, but am interested in that side of things, especially as the >> above compiler appears suboptimal in terms of copy elision and RVO. I am >> wondering for example whether are there any (compiler-specific) factors >> which could mitigate against the performance benefits of doing a move vs >> a copy of a vector, using these libraries, for example. >> > > Hi, > > unfortunately Boost.Move and Boost.Container are not working up to now > on Sun c++ even on trunk (1.49). See > http://www.boost.org/development/tests/trunk/developer/container.html. > > Best, > Vicente Thanks for pointing me to that. In general is there anything more detailed than pass/fail available to look at? Is the assumption that something with so many fails it not fixable one the library side, and is not worth investigating? Regards, T.

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[docs][crc] Did I do new documentation correctly?
by Daryle Walker 08 Jan '12

08 Jan '12

I completely redid the documentation for Boost.CRC in changeset [76335]. It uses Doxygen and Quickbook. I guessed on how to do it by copying files from Boost.Move. But I only did stuff within the BOOST_ROOT/libs/crc/* directory. I didn't make changes to other directories, especially the BOOST_ROOT/doc/* directory. Is stuff in that directory supposed to be automatically built? Other concerns: 1. The quickbook/doxygen system doesn't seem to handle "\todo" constructs correctly. 2. Is there a way to #define various common macros, like BOOST_STATIC_CONSTANT, so they get expanded correctly in Doxygen? Is there a "Doxyfile," or can the needed Doxygen parameters be tweaked in the Jamfile.v2? 3. I guessed that the next release will be "1.49.0", is that right? 4. Content-wise, did I miss anything? Daryle W.

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compile time parser generator
by Martin Bidlingmaier 08 Jan '12

08 Jan '12

Hello, with c++11's constexpr it got possible to parse strings in c++ at compile time. I've written a parser generator to create an AST for a given EBNF syntax at compile time, which can be traversed at both run time and compile time (actually, parsing can take place at run time, too, but it's probably rather slow). At the moment, the only compiler I know of that implements enough of c++11 features is gcc (version >= 4.6). Is refining my implementation worth the effort, has such a library a chance to make it into boost? Is maybe somebody already working on this? Sincerely, Martin Bidlingmaier -- NEU: FreePhone - 0ct/min Handyspartarif mit Geld-zurück-Garantie! Jetzt informieren: http://www.gmx.net/de/go/freephone

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no match for ‘operator=’ error with circular_buffer iterator when addressing buffer by reference?
by Bernd Prager 08 Jan '12

08 Jan '12

I am trying do use a circular_buffer iterator and run into problems when I try to write a copy constructor for my class. g++ (GCC) 4.5.3 generates following error: Test.cpp: In copy constructor ‘Test::Test(const Test&)’: Test.cpp:23:18: error: no match for ‘operator=’ in ‘it2 = boost::circular_buffer<T, Alloc>::begin() const [with T = int, Alloc = std::allocator<int>, boost::circular_buffer<T, Alloc>::const_iterator = boost::cb_details::iterator<boost::circular_buffer<int>, boost::cb_details::const_traits<std::allocator<int> > >]()’ /usr/local/include/boost/circular_buffer/details.hpp:253:15: note: candidate is: boost::cb_details::iterator<Buff, Traits>& boost::cb_details::iterator<Buff, Traits>::operator=(const boost::cb_details::iterator<Buff, Traits>&) [with Buff = boost::circular_buffer<int>, Traits = boost::cb_details::nonconst_traits<std::allocator<int> >, boost::cb_details::iterator<Buff, Traits> = boost::cb_details::iterator<boost::circular_buffer<int>, boost::cb_details::nonconst_traits<std::allocator<int> > >] What do I miss. Can anybody help? Thank you, -- Bernd #include <boost/circular_buffer.hpp> class Test { public: Test(); Test(const Test&); private: boost::circular_buffer<int> b; }; Test::Test() { b.resize(10); } Test::Test(const Test &t) { b.resize(10); size_t s1 = b.size(); size_t s2 = t.b.size(); boost::circular_buffer<int>::iterator it1 = b.begin(); boost::circular_buffer<int>::iterator it2 = t.b.begin(); } int main() { Test *t = new Test(); return 0; }

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Re: [boost] [Boost.smart_ptr] Thread Safety
by Thomas Jordan 08 Jan '12

08 Jan '12

Message: 7 Date: Sat, 07 Jan 2012 16:49:07 -0500 From: Dave Abrahams <dave(a)boostpro.com> To: boost(a)lists.boost.org Subject: Re: [boost] [Boost.smart_ptr] Thread Safety Message-ID: <m24nw7p4j0.fsf(a)pluto.luannocracy.com> Content-Type: text/plain >on Sat Jan 07 2012, "Thomas Jordan" <thomasjordan-AT-btinternet.com> wrote: >> Hi, >> Is shared_array completely thread-safe, including >> destruction/reference counting? From the code in >> /boost/detail/sp_counted_base_pt.hpp it looks like it probably is but >> according to >> >> http://www.boost.org/doc/libs/1_33_1/libs/smart_ptr/shared_ptr.htm#ThreadSa… >I can't reach that (very ancient) page right now, but... The documentation for this is example is the same in the latest v1.48 release. >> // thread A >> p3 = p2; // reads p2, writes p3 >> >> // thread B >> // p2 goes out of scope: undefined, the destructor is considered a "write >> access" >> >> shared_ptr isn't completely thread-safe for simultaneous read and >> write/destruct access? The same would presumbly apply to shared_array? >> Maybe I've missed something, are there compile-time configuration >> options to determine level of safety? >shared_ptr<T> is almost exactly as threadsafe as T* is. In this case, >thread A has a reference to an object on B's stack. That object is >called p2. If thread A tries to use that object's value while the >object is being destroyed, yeah, that's a race condition. >The way to avoid this situation is for thread B to pass p2 to thread A >by value, thus creating p2a, which thread A can read without concern. >Now there's no race condition. Note: this change does /not/ cause the T >object held by p2 to be copied. Thanks, I think my confusion arose from my inferring that the P2 in thread A in this example was shorthand for P2a, i.e., a copy of the actual P2 in thread B. Makes sense as per your interpretation. Regards, T.

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[Boost.Poly] Runtime Concepts
by Thomas Jordan 08 Jan '12

08 Jan '12

Hi, Forgive me if this post strays into territory beyond Boost, but I was looking at the Adobe library http://stlab.adobe.com/group__poly__related.html and some of the research papers by Sean Parent et al. describing it, which I guess many people on this list will be familiar with. Is there any reason why this library/something akin has not been put into Boost? Is it simply that it will always live in Adobe Source Libraries and there is no point duplicating in Boost? Second question - the research papers on this seemed to peter out around 2009, is there any further work going on, or has this approach been taken as far as deemed interesting, or even been informally deprecated in favour of something else? Regards, T.

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[Boost.smart_ptr] Thread Safety
by Thomas Jordan 07 Jan '12

07 Jan '12

Sorry, please ignore my previous post - finger trouble. The question is as follows: ------ Hi, Is shared_array completely thread-safe, including destruction/reference counting? From the code in /boost/detail/sp_counted_base_pt.hpp it looks like it probably is but according to http://www.boost.org/doc/libs/1_33_1/libs/smart_ptr/shared_ptr.htm#ThreadSa… // thread A p3 = p2; // reads p2, writes p3 // thread B // p2 goes out of scope: undefined, the destructor is considered a "write access" shared_ptr isn't completely thread-safe for simultaneous read and write/destruct access? The same would presumbly apply to shared_array? Maybe I've missed something, are there compile-time configuration options to determine level of safety? Regards, T.

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